AUTHOR=Ning Lin , Geng Yang , Lovett-Barron Matthew , Niu Xiaoman , Deng Mengying , Wang Liang , Ataie Niloufar , Sens Alex , Ng Ho-Leung , Chen Shoudeng , Deisseroth Karl , Lin Michael Z. , Chu Jun TITLE=A Bright, Nontoxic, and Non-aggregating red Fluorescent Protein for Long-Term Labeling of Fine Structures in Neurons JOURNAL=Frontiers in Cell and Developmental Biology VOLUME=10 YEAR=2022 URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2022.893468 DOI=10.3389/fcell.2022.893468 ISSN=2296-634X ABSTRACT=

Red fluorescent proteins are useful as morphological markers in neurons, often complementing green fluorescent protein-based probes of neuronal activity. However, commonly used red fluorescent proteins show aggregation and toxicity in neurons or are dim. We report the engineering of a bright red fluorescent protein, Crimson, that enables long-term morphological labeling of neurons without aggregation or toxicity. Crimson is similar to mCherry and mKate2 in fluorescence spectra but is 100 and 28% greater in molecular brightness, respectively. We used a membrane-localized Crimson-CAAX to label thin neurites, dendritic spines and filopodia, enhancing detection of these small structures compared to cytosolic markers.